A Study Of VSCF AC Excited Wind Generator System And Its Controlling Principles

In lately years, people widely pay attention to wind energy because it is a regenerated cleanness energy. It began development in high rate 20 years before. It is a fact that the variable-speed constant-frequency (VSCF) AC exited wind generator system is a main subject in the wind electric power generator schemes. It very fits for wind electric power generation with VSCF because it can capture as much energy as possible. Also AC exited generator have many excellent characteristics, it may improving the stability of electric power system, its rotor speed may adjustable, it have abilities for active and reactive power regulating in self-help ways, it not lose steps even when operated in deep lead phase, so it especially applied in wind electric power plant and pumped-storage hydraulic power plant. Also the 'green' converter-matrix converter is planned in this paper.In this article a new type wind generator-AC exited wind generator is introduced which new technology scheme by the variable-speed constant-frequency methods at the present time. The thesis mostly studies the way of some control methods and analysis the characters of VSCF wind power system. It presents the principle of VSCF wind power system and the differences between AC exited generator and Synchronous Asynchronous generators. Analyzed the balance of its energy. It also builds the mathematic model of all section of VSCF AC exited wind power generation system on a-b-b and d-q coordinate system by the coordinate commutation technology. The thesis gives the characteristics of torque, active power, reactive power and the steady-state analysis of it. It proves that the capability of wind generator is determined to slip, the amplitude and phase of rotor voltage, the phase dispatch between stator voltage and rotor voltage. Also this paper investigates the control model based on the stator field-oriented vector control. This paper discussed the newly excitation system-matrix converter and compares the const speed const frequency Asynchronous wind generators and VSCF generator system. Finally studies wind energy tracing control, grid-connection control and leading phase control. This thesis shown that VSCF AC exited wind power system with stator field-oriented vector control has a series of good performance and all the control schemes which had been introduced in this paper has its feasibility.